What if Ed’s parents were getting him a new bed, and he had to decide what size bed is best for him? Initially he decided that he would like a king bed. Upon further research, Ed discovered there are two types of king beds, an Eastern (or standard) King and a California King. The Eastern King has
dimensions, while the California King is
(both dimensions are
width
length
). Which bed has a larger area to lie on? Which one has a larger perimeter? If Ed is 6’4”, which bed makes more sense for him to buy? After completing this Concept, you'll be able to use your knowledge of rectangles to answer these questions.

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Guidance

To find the
area of a rectangle
calculate the product of its base (width) and height (length)
. The
perimeter of a rectangle
is
, where
is the base (or width) and
is the height (or length). If a rectangle is a
square
, with sides of length
, the formula for
perimeter
is
and the formula for
area
is
.

Concept Problem Revisited

The area of an Eastern King is
and the California King is
. The perimeter of both beds is 312 in. Because Ed is 6’4”, he should probably get the California King because it is 4 inches longer.

Vocabulary

Perimeter
is the distance around a shape. The perimeter of any figure must have a unit of measurement attached to it. If no specific units are given (feet, inches, centimeters, etc), write “units.”
Area
is the amount of space inside a figure. Area is measured in square units.

Guided Practice

1. Find the area and perimeter of a square with side 5 in.

2. Draw two different rectangles with an area of
.

3. Find the area and perimeter of a rectangle with sides 7 in and 10 in.

Answers:

1. The perimeter is
and the area is
.

2. Think of all the different factors of 36. These can all be dimensions of the different rectangles.